Enemy = function( x, y, z )
{
    this.initComponent( x, y, z );
    
    this.update = function( elapsedTime, context )
    {
        this.y += 1.5;
     
        if ( !this.isValid() )
        {
            core.remove( this );
        }
        
    };
    
    this.draw = function( elapsedTime, context )
    {
        context.strokeStyle = "#000000";
        context.fillStyle = "#FFFF00";
        context.beginPath();
        context.arc( this.x, this.y, 20, 0, Math.PI * 2, true );
        context.closePath();
        context.stroke();
        context.fill();
    };
        
};

Enemy.prototype = new Component;